Method of producing nitrogen compounds during the dry distillation of nitrogenous fuel



can be readily separated from the new r0 7?) r p n] r Pieiahhwl "WALTEROS'I'WAL'D, OF GROSSBOTHEN, NEAR LEIPZIG, GER/TEA:

AEiSaIGrNCUR, BY

OF DELAWARE.

METHOD GT3 PRODUCING NITROGEN COMPOUNDS DURING- il-IE DRY DISTILLATIONOF NITROGENOUS FUEL;

No Drawing. Application filed September '7, 1916, Serial lilo. 118,838.Renewed January 27, 1926.

Specification of Letters Patent.

Serial No. 354,748.

To all 21:71am it may concern:

Be it known that LWVALTER QSTWALD, of Grossbothen, near Leipzi Germany,Hans Dowa, have invented a certain new and usei'ul Improved Method ofProducing Nitro' gen Compounds During the Dry Distillation ofNitrogenous Fuels, of which the following is a specification.

During the dry distillation of a charge composed of coal mixed withchlorids, it is frequently found that in the pipes of the plant thicktar-like masses are formed which principally consist of ammonium chloridand cause serious trouble in the operation of the plant. For obviatingthis defect it has been customary to use so-called wet receivers inwhich the ammonium compounds in question are carried away partly inaqueous solution.

in the process according to my present invention the opposite procedureis adopted. The invention consists in converting the nitrogen at theoutset uniformly into the form of ammonium chlorid, so that it can bereadily condensed.

For this purpose, the nitrogen may, for instance, be converted intoammonium chlorid by the addition of chlorids to the charge to besubjected to dry distillation. The temperature of sublimation ofammonium chlorid is about 450 O, so that it gases by fractionalcondensation.

My present invention, therefore, essentially consists in converting intothe form of ammonium chlorid the entire nitrogen, which can be obtainedby the dry distillation of the charge. The nitrogen contained in thecoal may be divided into two parts, namely into one which may easily beobtained in a bound form, that is the so-called non-fixed nitro-' gen,and into a second part which is not liberated before the pyrogenousdestruction 0-2 the colre has started. This latter part may bedesignated fixed nitrogen. The entire amount of nitrogen is divided inapproximately equal parts into fixed and noni'izred nitrogen. In theprocess according to my present invention only the non-fixed nitrogencan be obtained. It is, however, pos sible by means of my invention toprevent the combustion of the nitrogen compounds which are produced fromthe non-fixed nitrogen by converting the ammonia into ammonium chlorid.The material increase in the yield of nitrogen is thus partly explained.When the distillation is carried out in the mannercustomary heretofore,only 15% of. the nitrogen of the coal can be won, of the nitrogenremaining as fixed nitrogen in the coke and 15% in the tar. Theremaining part of non-fixed nitrogen (about 15% to 20% of the totalnitrogen) can be obtained in the process according to my presentinvention if care is taken that the formation of ammonium chlorid is notdiminished owing to lack of water or steam. in order to bind thisremaining part of the nitrogen which may be obtained during the drydistillation in the form of ammonium chlorid, according to my inventionwater or steam is introduced during formation of the ammonium chlorid.This water may consist of the moisture contained in the coal, or afurther addition of water may be made, and the action may be enhanced bythe water of hydrated salts; however, the preheating of the charge inthe retorts should not be suiiicient to expel, as steam, the water addedto supplement the moisture contained in the coal. Owing to the additionof chlorids and by regulating the supply of water or steam, it ispossible to set free the two constituents of the ammonium chlorid insuch a manner that they will be equivalent to each other at any momentof the carbonizing period. This is of special importance, since anexcess of free ammonia might be decomposed by glowing walls and sincefree hydrochloric acid is lia ble to injure the apparatus. The chlorideused, may be the chloride oi the alkaline earth metals or hydrochloricacid either in liquid'or gaseous form.

At the same time, obtaining the nitrogen in form oi ammonium chlorid hasmaterial advantages as regards the method or working itself. Ammoniumchlorid is uniformly volatile, this being exactly contrary to most othernitrogen compounds which have heretofore been found with the usualmethods in gas-water and in other constituents of the distillationgases. By simply washing the gas with water and cooling the solution tothe temperature of crystallizatiomit is possible to obtain directly, apure marketable ammonium chlorid instead of theusual complicated mixtureof various kinds of nitrogen compounds, all employment of sulfuric Thesolution obtained by the present method is preferably evaporated in aneutral or slightly alkaline state, and thls can be effected withoutmaterial expense by waste heat, the ammonium chlorid being obtained.

directly in crystalline form. Lastly, obtaining the nitrogen in the formof ammonium chlorid has the further advantage that the chlorid caneasily and cheaply .be freed from impurities not only byrecrystallization, but also by re-sublimation. Ammo-' nium chloridcontaining 25% nitrogen is richer in nitrogen than-the ordinary com-'IIlGIClEll ammomum sulfate.

1 claim 1. In the dry-distillation or coking of a nitrogenous fuel, theprocess of obtaining as a by-product the non-fixed nitrogen of the fuel,which consists in mixing a chlorid with the fuel, in heating the mixturein a closed chamber and supplying steam thereto with the exclusion ofair, whereby hydro chloric acid is produced and the nitrogen of the-fuelis converted into the form of ammonium chlorid, and in subsequentlyseparating the ammonium chlorid from the remaining products;substantially as described.

2. In thedry-distillation or coking of a nitrogenous fuel, the processof obtaining as a 'by-product, the non-fixed nitrogen of the fuel, whichconsists in mixing a chlorid with the fuel, in heating the mixture in' aclosed chamber and supplying steam thereto with the exclusion of air,the quantity of admixed chlorid being approximately equivalent to thepercentage of non-fixed nitrogen in the fuel, whereby hydrochloric acidis produced and nitrogen of the fuel is converted into the form ofammonium chlorid,

and in subsequently separating the ammonium chlorid from the remainingproducts.

substantially as described.

3. In the dry dlstillation or coking of a nitrogenous fuel, the processof obtaining as a by-product, the non-fixed nitrogen of the fuel, whichconsists. in'-mixing a hydrated chlorid with the fuel, in heating themixture in a closed chamber and thereby generating steam therein withthe exclusion of air, whereby hydrochloric acid is produced and nitrogenof the fuel is converted into ammonium chlorid, and in subsequentlyseparating the ammonium chlorid from the remaining products,substantiallyas described.

4. In the dry-distillation orv coking of a nitrogenous fuel, the processof obtaining as a by-product, the non-fixed nitrogen of the fuel, whichconsists in mixing a chlorid with the fuel, in heating. the mixture in'a closedchamber and generating steam therein with the exclusion of air,whereby hydrochloric acid is produced and the nitrogen of the fuel 1sconverted into ammonium chlorld, and in subsequently scrubbing the gasesproduced.

With water and thereby obtaining the ammonium chlorid in the form of anaqueous solution, substantially as described.

In testimony whereof I affix mysign'ature in presence of two witnesses.

. WALTER OSTWALD.

Witnesses:

RUDOLPH FRIOKE, 'THEKLA Fmomi.

